Santa Cruz County Sheriff Jim Hart on Wednesday became the first sheriff to endorse the so-called sanctuary state bill, which would prohibit state and local law enforcement agencies from using resources for immigration enforcement.

In a letter to state Senate President Pro Tem Kevin de León (D-Los Angeles), who introduced the legislation, Hart said Senate Bill 54 would improve public safety and provide clear standards for local law enforcement agencies.

"The fear of detention, deportation, and family separation is very real and is having negative impacts for public safety and law enforcement," the letter states. "Public safety is not enhanced when local law enforcement officers enforce immigration laws or act in a manner that causes suspicion within the diverse communities they serve."

The support is a boon for De León, who has sought to amend the bill to address law enforcement concerns and is facing increasing fire from opponents. A speaking engagement just this weekend at UC Riverside turned heated as audience members taunted De León, and staff members said university police insisted on escorting him out for his protection.

But tensions have flared in Santa Cruz between police and Immigration and Customs Enforcement's Homeland Security Investigations division after a series of joint raids on MS-13 gang members instead resulted in immigration arrests of people in the country illegally.